Type 2 adenovirus DNA can be cleaved with a combination of site-specific restriction endonucleases into 25 or more ordered fragments ranging from 4200 to 170 base pairs in length. The strands of many fragments can also be separated by gel electrophoresis after alkaline denaturation. The fragments and the separated strands can be used to construct a detailed replication map. In addition to merely locating origins and termini for replication, the map can indicate whether or not synthesis occurs by a strand displacement mechanism and if replication proceeds through the ends of the chromosome. In fact, adenovirus replication may be quite complicated: a preliminary map reveals several origins at internal positions as well as at both ends of the molecule. The role and control of these initiation sites are not yet known. BIBLIOGRAPHIC REFERENCE: Pearson, G.D. (1975). Intermediate in Adenovirus Type 2 Replication. J. Virol. 16: 17-26.